Mediterranean spotted fever-like illness in Sardinia, Italy: a clinical and microbiological study

Area of Science:

• Infectious Diseases
• Molecular Diagnostics
• Epidemiology

Background:

• Rickettsioses are emerging infectious diseases in Europe, influenced by climate change and environmental factors.
• Mediterranean spotted fever (MSF) is endemic in Sardinia, posing a significant public health challenge.
• Understanding the etiology and clinical presentation of MSF-like illnesses is crucial for effective management.

Purpose of the Study:

• To investigate the causes and clinical features of MSF-like illnesses in northern Sardinia.
• To compare the diagnostic accuracy of different laboratory methods for rickettsial infections.

Main Methods:

• Patient enrollment at the University of Sassari's Infectious Disease Unit.
• Diagnostic testing included ELISA, Indirect Immunofluorescence (IFI), and DNA isolation (real-time PCR and genotyping) from blood and eschar samples.
• Eighty-seven patients were included, with diagnoses including MSF, Q fever, and anaplasmosis.

Main Results:

• Mediterranean spotted fever (MSF) was the most common diagnosis (79%).
• Antibody-based tests (IFI and ELISA) confirmed MSF in less than 50% of cases.
• DNA isolation from eschar samples confirmed rickettsial infection in 77% of tested cases and identified the first case of Rickettsia monacensis in Italy.

Conclusions:

• DNA isolation is superior to antibody-based tests for diagnosing MSF-like illnesses, confirming diagnoses in 77% of cases.
• Molecular methods enabled the identification of a novel pathogenic Rickettsia species in Italy.
• Implementing DNA isolation is recommended for accurate etiological diagnosis and improved patient management of MSF-like illnesses.